1. Field of the Invention
This invention relates to systems and methods for storing and treating excess waste water from a sewer system such as a combined storm and sanitary sewer system or a sanitary sewer system.
2. Background Art
Combined sewer systems, i.e. sewer systems that carry both sanitary sewage and storm water run off still exists in many older cities built before it was common to separate storm and sanitary sewer systems. During heavy rain storms the sewage flow through the combined storm and sanitary sewer system may exceed the treatment capacity of the sewage treatment plant. In order to avoid dumping excess untreated sewage into receiving water body, such as a river, lake or ocean, it is common to create basins to store excess combined storm and sanitary sewage. After the rain event the sewage is reintroduced into the sewage system so that it can be processed by the sewage treatment plant when there is available treatment capacity.
Basins have historically been rather expensive to construct, particularly in the areas with limited land and high land costs. Many traditional basins also require substantial pumping equipment in order to discharge sewage to a waterway in the event that the basin capacity is exceeded. In order to eliminate the health risk of discharging raw sewage into a waterway, a basin system may include a system for introducing a disinfectant into the waste stream system and for separating solids as well as floatables from any basin discharge.